A Duluth beach walker came across these balls of fibrous stuff on a beach near the city’s Lakewalk, not long after a New Year’s Eve storm. The round bundles — about the size of a plumb — seemed to combine plant material and other things tightly wound with bits of plastic.

He left the bundles with his dad, long time resident Glenn Maxham, who took the oddities to the experts at Minnesota Sea Grant, a group that works to help preserve Lake Superior and its shores. Its members identified the things as “whale burps.”

Also known as surf balls, they’re are fairly common on ocean beaches worldwide.

But the source isn’t as cute as the name. The balls apparently start with human junk, like left over fishing line, or in this case, some kind of partially degraded black plastic mesh. Whipped by a good wind, the plastic rolls along a beach, picking up seaweed, twigs, grass, shell fragments or what ever gets in the way.

Sea Grant notes the damage discarded plastics do on water bodies worldwide. When the plastics break down they release suspected cancer-causing chemicals like styrene monomer and bisphenol A, also known as BPA. Sea Grant quotes a United Nations Environmental Program estimate that some 46,000 pieces of plastic float in every square mile of ocean.

Even on Lake Superior, about a third of the refuse collected in an annual beach clean up is plastic, trailing only behind cigarette butts, which account for half.

Sea Grant suggests no need to wait for the annual beach cleanup. Anyone can grab a plastic bag and hit the beaches, providing, of course, they’re not currently covered in snow.